Which expression is equivalent to the one below? 5^x

answers (multiple choice)
a. 5*5^(x-1)
b. 15^x/3
c. 15^x/3^x
d. (15/3)^x
e. 5*5^(x+1)
f. x^5

At school there are 526 students and 263 are girls about how likely is it that a randomly chosen student will be a boy

Prove (a) cosh2(x) − sinh2(x) = 1 and (b) 1 − tanh 2(x) = sech 2(x). solution (a) cosh2(x) − sinh2(x) = ex + e−x 2 2 − 2 = e2x + 2 + e−2x 4 − = 4 = . (b) we start with the identity proved in part (a): cosh2(x) − sinh2(x) = 1. if we divide both sides by cosh2(x), we get 1 − sinh2(x) cosh2(x) = 1 or 1 − tanh 2(x) = .

What is the missing reason in the proof? segment addition congruent segments theorem transitive property of equality subtraction property of equality?